Conventionally known power generation structures using a piezoelectric device includes, for example, a structure in which an electromotive force is generated by directly applying an external force to a piezoelectric device to deform it (e.g., see Patent Document 1) and a structure in which an electromotive force is generated by indirectly applying a force, such as wind or the like, to a piezoelectric device to deform it (e.g., see Patent Document 2).
Furthermore, as an electric apparatus to which a power generation structure using such a piezoelectric device is applied, a mobile phone including a secondary battery that can be recharged by the output of the piezoelectric device has been proposed (e.g., see Patent Document 3). This mobile phone obtains an electromotive force from the piezoelectric device deformed by a force applied when a user pushes an input key.